Originally posted by vonBaloney On the K-5, there is often a difference, but only like 1/3 of stop, never 1 or 2 stops.
It might depend on the lens*. I don't have a new body, but was able to document the difference with the K-7 when I demo'ed that camera. Take a look in your K-5 manual (Appendix, p 11) and note the lens/mode combinations with the text "but an exposure
error may occur".
Again...this is not Live View, but stop-down metering off the focus screen.
Steve
* I find that at apertures f/5.6 and narrower, the metering is generally pretty close and with my slower lenses the K10D just pretty well.
(Stop-down metering with the Pentax-M 50/1.7 vs. Pentax-A 50/1.7 wide open is a full stop difference on the K10D...just measured it.)